Process for the preparation of copolymers from linseed oil and styrene and the copolymers thus prepared



United States Patent Willem Johan Taat, Delft, Netherlands, assignor to Naamloze Vennootschap Scado Kunstharsindustrie, Zwolle, Netherlands, a corporation of the Netherlands Application January 28, 1953, Serial No. 333,835

Claims priority, application Netherlands February 11, 1952 4 Claims. (Cl. 260-23) N Drawing.

Co-polymers from styrene and drying oil are used, inter alia, as paint-binding agents and as raw materials for the preparation of alkyd resins.

These co-polymers can be prepared by heating'the components for a long time. Heating can be carried out both in the presence of a solvent and without the use of a solvent. When no solvent is added, polymerization catalysts are preferably added, in particular organic peroxides have proved to be useful as such.

In performing these processes various difficulties arise, however. The co-polymers formed are often turbid and dry to turbid varnish films. Turbidity is connected with the percentage of styrene or styrene mixture, and only a limited quantity can be co-polymerized together with the oil. When the styrene is partly replaced by a methylstyrene, the percentages of' styrene mixture, whereby clear products are still obtained, are, it is true, a little higher, but when working with the normal peroxidic catalysts, as for example benzoyl peroxide, it is not possible to add more than approx. 40% of styrene mixture to the oil, without turbid products being formed.

In the copending U. S. A. patent application No. 283,668, now abandoned, it has been suggested to efiect (to-polymerization in the presence of an organic peroxide with a high temperature of decomposition, which enables the formation of clear productswith a high percentage of styrene or styrene mixture. A drawback of all the clear products obtained in these ways is, however, that the flow of the paints and varnish prepared with them is insuflicient. In order to improve the flow-properties, instead of drying oil, pre-polymerized oil (standoil or bodied oil) can be copolymerized with styrene or styrene mixtures. As a result, however, the proportion of styrene or styrene mixture whereby clear products can still be obtained, is further decreased.

'It was now found, that by preheating drying oil after the addition of a slight quantity of selenium, the nature of the oil is afiected in such a way that it becomes an exceedingly suitable raw material for co-polymerization with styrene or mixtures of styrene and a methylstyrene, and that by this pre-treatment the percentage of styrene or styrene mixture which can be polymerized with the oil without yielding turbid products, is considerably higher than with non-pre-treated oil or oil which has been partially polymerized without the addition of selenium, while the products obtained have an excellent flow. With this heating the selenium is dissolved, presumably under formation of compounds.

It is known that selenium affects the cis-trans-isomerization of oleic acid.

Nothing could, however, raise the presumption that the oil would become more suitable as a raw material for styrene copolymerization by pre-treatment with selenium. When copolymerizing, this pre-treatment has the desired effect both with and without a solvent.

The use of the oil preheated in the presence of.

selenium, proved to have some more advantages if no solvent was added, for on co-polymerizing without sol vent a smaller proportion of catalyst is sufiicient than on using a non-pre-treated oil. Furthermore in this case, the heating time required for efiecting copolymerization is shorter than it another oil component is taken as a starting material. Preheating after the addition of selenium may, for instance, be carried out by heating the oil with 0.1% by weight of selenium at 240 C. for approx. 4 hours. At higher temperatures shorter heating-times are suificient; at lower temperatures the times required for preheating are longer. Below 200 C. the velocity at which the oil is modified after the addition of selenium is so small, that preheating is fairly impracticable at this temperature.

The time required for preheating also dependson the way in which the following co-polymerization is carried out, and may differ as to whether or not a solvent is present. Also the nature and quantity of catalyst with which the following co-polymerization is carried out has an influence on the time required for preheating. If, for instance, one wishes to co-polymerize 55% by Weight of linseed oil with 45% by weight of styrene without a solvent, with di-tertiary-butyl peroxide as catalyst, then 8 hours preheating of the oil with selenium is not sufficient to obtain clear products if 0.45% of catalyst (calculated on styrene and oil) is used; with the use of 0.9% of catalyst, clear products are indeedobtained and with v the use of 1.35% of catalyst 2 hours preheating at the same temperature is already sulficient.

The preheating time also depends on the quantity of selenium with which it is carried out. With quantities of over 0.1%, however, the oil tends to discolour, which is undesirable for raw materials for varnish. At the same time the difliculty arises that this preheating should be carried out in such a way that the gaseous selenium-hydrogen compounds formed are carefully removed, since they cause an unbearable smell. At percentages far below 0.1% of selenium the preheating times become considerably longer and therefore preheating is preferably carried out with a quantity of selenium of 0.05 to 0.2% by weight, calculated for oil. In the appended table a few comparative tests of co-polymerization with unpreheated oil and oil preheated without and in the presence With every test the percentage of catalyst was 3% by weight of the quantity of styrene. The heating scheme 7 was as followsz' I Stage 1.--Heatingthe oil to -465" C. and adding the styrene (mixture), in which the catalyst has been dissolved, over a period of 6 hours;

Stage 2.G-radually increasing the temperature to 250 C. over a period of 5 hours;

Stage 3.Heating at 25 0 C. for 6 hours;

Stage 4.--Quick1y raising the temperature to 300 C. and heating at this temperature for 4 hours.

It is true that these periods fior working with the oil which has been preheated with selenium are unnecessarily long, but if in one case another heating scheme should be used than in the other, this could give rise to an incorrect interpretation of the observation results and a wrong interpretation of the conclusions to be drawn therefrom.

Table] Pretreatment Relative proportions.of- Catalyst Appearance o-- with 0.1%

1 selenium Stage for g 7 Flow of Number linseed oilf'perstyrene, a-methyl- Percent sampling .varuish I cent byaweight pereent= styrene;- type by wt. oil Varnish film tempj, time; V by weight 'per cent on mix- 1: G. hours" .t byweight ture 1n strindoili 55- 45 135' after stagei3g opalescent turgood-. Samson: 55 45 1.35 after'stage 4- Augpgli: tur idf' f e;

-i i j V1 2* linseed.w 55 45 '1. after stage 3 clear slightly poor. 7 oil. I opalescent. 2b 55. 455 1.35 after stage 4 opalest- ,do I Do;

I cen f L35 after-' stageziingood 45? 1.35- aiterstage 4. Do. l 60 1. 8 alterstage'iL Do. 60 1. 8 after stage 4- 7 Do. 31.5 '13-. 1.35- after'sta'geis. d h 3115 L 1395- 1.35 after stage 4.1- Do.

. 6a 38.5 16.5 undo, 1.65 afte'rstage 31.. Do.

1 d: tflb: p;o.=ditertiary butylp'eroxider {From tests" 111 1 to '45 it appears"thet'iwitlipreheated '"oil to: which selenium? his :beenadded "a much" higher percentage of styrene'is'able*toco polymerize witlitheoil to clear products than is'possible without'this'preheating', while better jflowing 'productsare obtainedthen iwith'nona 30 preheated oil." Onthe' other. hand, bythe use 'ofla-rger quantities .of"styrene the flow" is generally unfvourably affected. On comparing tests li and b.with"3 and 4&1 'andf b the considerable advantage of theuse -oflpreheated oil .to' which." selenium has "been" added"over the use of 35 bodied oil, which"hasilconsequentli i beeif'hea'ted iwithbut the addition of selenium; is also apparent:

From tests 5a to 8b, whereby:benzoylpertnridewas:v used as catalyst; it .ap'pe'ars tli'atialsb; with? mixtures of styrene and u rnethylstyre'neand Japatalyst "which is de' composed at .21 lower temperature, preheatin'g 'ofthe oil" 7 after the addition of selenium" gives 'proppi'tibn'ally the same advantages; V V

Finally it"'may,beremar ked that when %.by weight of non-pretreated linseed 1 oil and 145% ibyl-weiglit" of styrene with."di tertisry;butyl'iperoxide as. cata'lys'tlere.

preheating consists'in 8 l1'burs heating-after the additi6n of 0.1% of selenium at Z4Q CT Howevenfwith th'e use OJf'-0. 65% -0f-Cata1ySf, co polymerizati'on procee'ds' enti rel in the manner desired.

As stated before; the heating-'itimed 'with 'the use of oilpre-heated affer -additionvof seleniurmsmaybe fshorter;

j than with the use of untreated linseed oil. Thus iflprovd to-be possible to obtaingood;clear'PrOdHctsQby-preheating linseed oil after the additibn' of 0.-1%'. of:.selenium Fat 250 C. for 4 hours, heatingathis'product with: -1. 35.%:-of

di-tertiary-butyl peroxide: (percentnby' *weight,'2 calculated on oil and styrene together) as catalysgigradually add-ingi the styrene to the .oil'in approxf2fhourstatrz165 C.,;ra.'is

;l; A process of copoljimerizingilihseed foil'fwitlgi styrene V to torm .clear. polymers which dry to e-lean films, .com-. prising the steps.pfsheatingflinseedmoil..atsa.temperature.-

witlr' -styrene .soasto fonnva cleartcopplyrner otsaid lin seed oil I and; styrene which upon. drying .foims aclear filmu V a Y 5 24A process ofcopplymerizing linseedpilwith styrene to form-fcleanpolyniers wwhihldry to clear. .filiiis, zoom-.1; prising the..step's of :heatin ga1inseed..-oil vatfa ternperature -of .about 240 CT for, about l -hours withi about f 051% by we ight wofflj'sel'enium;l and copolymeriz irigtheethus:

selenium-treated linseed; oil-. with.. styrene so as. to form..a clear; copolyrner 7 0f seidhlinseed loll andistyrene: upomd-rying tormsa=cleat film... I

'3 A processeofgzopplymeriiing linseedhilmitlistyrene tot-fdrmuclear, pplj n ers meudr meua prisinggth er steps of heatirig linseedr il lat:v .211 temperature g selenium; :andflcop olymeriz zing l the. thus selenium-treated linseed -oiL withwsty rene Lin the; presence off. anlprg alnic peroxide as catalyst :so.as t-oflfdrmua clear..copolrner of'. said linseedsoil .andstyrenetwhich upon: d ryi-rig forms at. clearfilm. 'l' 4 4.: Thelproduct of. theprocessoficlaimsll.

I g i References Cited Qinl theA file .of ifthisipatent V UNH ED SIA 'I'ES' PATElSTS 

1. A PROCESS OF COPOLYMERIZING LINSEED OIL WITH STYRENE TO FORM CLEAR POLYMERS WHICH DRY TO CLEAR FILMS, COMPRISING THE STEPS OF HEATING LINSEED OIL AT A TEMPERATURE ABOVE 200* C. WITH 0.05-0.2% BY WEIGHT OF SELENIUM; AND COPALYMERIZING THE THUS SELENIUM-TREATED LINSEED OIL WITH STYRENE SO AS TO FORM A CLEAR COPOLYMER OF SAID LINSEED OIL AND STYENE WHICH UPON DRYING FORMS A CLEAR FILM. 